): old age or hld?

My oldest boy Albie is around 29 months now. For about 6 months (maybe longer) he's been wobbly on his feet, for a while we thought he had hld but then he seemed to get better. He's been up& down hill a bit, but doing okay most of the time. Today he seems a lot worse, he's really bad on his feet now, his wobble is so bad he can't go more than ten steps without falling over. When eating he still manages with two front hands sometimes, but tonight it's mostly just one hand. Since Monk went downhill we'd been giving Albie extra meals at night, including senior aid. He's down to 450g now, which is 200g less than he was at his heaviest. He was a bit chubby then, so really he's about 100-150g less than when he looked his best. The weight loss has been gradual over a few months, so i'm not too worried, and he seems to be maintaining his weight at the minute.

Here's a video from tonight:
https://youtu.be/L83UjgWmjk8
i'll link another when it's uploaded.

Basically, does it look like hld or just old age? Monk's back legs were going a bit before she went downhill..
I guess it doesn't make much difference really what it is..
I'm wondering when it's best to move him into his retirement cage. He's in with 3 other boys, one (chandler) about 27-29 months and 2 are 10 months. He'd be going into his retirement cage with, at least, chandler, but i'd really like all 4 to go in together so i'd not have to worry about reintroing chandler when albie leaves us. They get plenty of freerange, but do you think they young ones would be too limited in the retirement cage? It's a rabbit one.. not sure of measurements, but longer than the furet plus.. Then again, they might eat all his food on him..
Help? ):

looks like hld to me, but really he seems to be doing so well I wouldn't worry much, especially at his age I know what you mean about it seemingly getting better and worse, Monty's does that too, but he's much wobblier at the back. Personally I'd move them all in there while Albie is still doing well, so it wont be a big shock to him later on in life - but maybe more experienced owners would disagree. I'd then free range the others when the food goes in if you're worried he isn't getting enough, so he gets first pick, though tbh I'm finding that leaving Monty to his own devices is working very well, he's doing a lot better with the new boys challenging him than when he was with Theo and he could just lie in bed all day.

Albie's a gorgeous boy anyway, he looks great for his age I hope he continues to do well

thanks katherine.
anyone else have any ideas?